"When I was writing her in the first series, it was almost impossible not to have her dominate,” Millar tells The Hollywood Reporter. "There would be moments when I’d just let her take over and completely outshine even the main character so I realized she had it in her to handle a book of her own."

Originally another artist was slated to the draw the book as it was going to be a companion mini-series to the recently completed Kick-Ass 2, but Millar opted to have the book come out after and keep all the Kick-Ass universe with Romita.

The book takes place before the events in Kick-Ass 2, and places Hit-Girl, aka Mindy Macready, in more ordinary settings, such as school.

"Hit-Girl can eviscerate a drug deal, but how (does) Mindy react when girls at school tease her about her slightly lame clothes or complete lack of pop culture awareness? She’s grown up in a vacuum so seeing this slightly more vulnerable side to her opens a lot of interesting stuff among the beheadings,” says Millar.

The new mini-series will also show how she trains Kick-Ass, introduced Uncle Ralphie, who was one of the bad guys in Kick-Ass 2, and picks up Red Mist’s story after the original mini-series.

Millar, one of the big names in comics thanks to his work at Marvel, is in the midst of a very big year, with several creator-owned books including Supercrooks and The Secret Service hitting stands. But he admits that Hit-Girl and Kick-Ass are a breed apart.

"I’ve been very lucky in that all my new characters have caught on, but these two have really been the break-outs," he says. "I think the enthusiasm I have for them is contagious because we’ve generally outsold most of the big Marvel and DC titles since we started and I’ve literally seen strangers dressed as these guys in the street in Halloween. I’ve never enjoyed writing characters as much as I enjoy writing these two. Hit-Girl maybe a little more, since she’s more outrageous."